Small internal combustion four cycle engines typically include a cam gear and a pair of cam lobes mounted on a camshaft. The cam gear meshes with a crankgear mounted on a crankshaft, thereby rotating the camshaft in timed relation to the engine cycle. Each rotating cam lobe reciprocates a push rod, which in turn acts on a rocker arm to alternate an intake valve or an exhaust valve between open and closed positions. In the case of an overhead cam type engine, the rocker arms normally act directly between the cam lobes and the valves.
Less common constructions for actuating the intake and exhaust valves have also been proposed in which V-shaped or frog-leg-shaped followers bear directly against a cam surface. For example, U.S. Pat. No. 4,736,717 to Fujikawa et al. discloses a four-cycle engine having a pair of bell cranks fit onto separate pivot shafts. One arm of each bell crank follows a cam surface, while another arm contacts the lower end of a valve stem. Also, U.S. Pat. No. 4,510,897 to Hatz et al. discloses a mechanism for actuating the valve rockers of an internal combustion engine. The mechanism includes a pair of cam followers, each of which engages a cam surface and a push rod.
The followers utilized in internal combustion engines such as those discussed above are typically cast or forged. While these processes produce workable parts, they are relatively time consuming and costly. It would be advantageous to devise a method of making a follower by a less expensive process, for instance forming the follower from common sheet metal.